Design Optimization of Non-Axisymmetric Vane for an Axial Compressor under Inlet Distortion

The flow field at the inlet of compressors is generally encountered combined total pressure and swirl distortion for either aircraft engine with S-duct or gas turbine with lateral air intake. This inevitably deteriorates compressor aerodynamic performance, including not only the efficiency or pressure ratio but also the operation stability. In order to conquer this issue, appropriate measures such as integrating flow control techniques and modifying inlet or compressor design are of benefits. Due to this motivation, this article develops a full-annular two-dimensional (2D) and a partial-annular three-dimension (3D) optimization strategy for non-axisymmetric vane design. Firstly, two numerical simulation methods for evaluating performance of full-annular 2D vane and compressor with partial-annular 3D vane are developed. The swirl patterns at the inlet of a 1.5-stage axial compressor are analyzed and parametrized, and the parameterization is transferred to characterize the circumferential distribution of geometrical parameters of the vane profile. These approaches dramatically reduce computational simulation costs without violating the non-axisymmetric flow distortion patterns. Then various full-annular 2D sections at different radial locations are constructed as design space. The designed vane is reconstructed and 3D numerical simulations are performed to examine performance of the non-axisymmetric vane and the compressor with it. Also, partial annular 3D optimization is conducted for balancing compressor efficiency and stall margin. Results indicate that the designed non-axisymmetric vane based on full-annular optimization approach can decrease the vane total pressure loss under the considered inlet flow distortion, while those using partial-annular optimization achieve positive effects on compressor stall margin.